Key to Wisconsin Pycnanthemum

Author: John G. Zaborsky

• 1a. Stems pubescent on the sides and angles; leaves often over 7 mm wide P. verticillatum

• 1b.Stems glabrous or pubescent only on the angles; leaves less than 7 mm wide (rarely wider) 2

• 2a. Calyx lobes acuminate, often with a subulate tip, the outer faces of the tips puberulent; stems glabrous; leaves glabrous, the widest ones no more than 2 (–3) mm wide P. tenuifolium

• 2b.Calyx lobes triangular, without subulate tips, the outer faces of the tips densely pubescent; stems pubescent along the angles with spreading and/or incurved hairs; leaves pubescent on the margins and abaxial veins, widest leaves 5 mm or more wide P. virginianum